Fan assembly and storage chamber utilizing a fan assembly

ABSTRACT

A fan assembly ( 14 ) for ventilating an essentially closed chamber such as an inflatable storage chamber for a motor vehicle comprises a base plate ( 17 ) for mounting over an opening through a wall ( 13 ) of the chamber, the base plate defining an aperture ( 21 ) therethrough and an electrically-driven fan ( 28 ) being arranged to draw air from a first plenum ( 31 ) upstream of the fan and drive the drawn air into the chamber. An air treatment unit ( 25 ) is disposed over an opening through the base plate between the chamber and the first plenum ( 31 ). A first filter ( 22 ) is disposed in an opening between the first plenum ( 31 ) and the external atmosphere ( 35 ). In this way, air driven into the chamber by the fan ( 28 ) will be a mixture of air drawn from the external atmosphere through the first filter ( 22 ) and air drawn from the chamber through the air treatment unit ( 25 ) into the first plenum ( 31 ), to be recirculated into the chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national stage application of InternationalApplication PCT/GB01/00467, filed 7 Feb. 2001, which internationalapplication was published on 10 May 2002 as International Publication WO02/36904 in the English language. The International Application claimspriority of Great Britain Patent Application No. 0026805.2 filed 2 Nov.2000.

BACKGROUND OF THE INVENTION

This invention relates to a storage chamber in the form of anessentially closed space in conjunction with a fan assembly forventilating that space.

A known form of inflatable storage chamber for articles such as vintagecars and motor-cycles or other delicate machinery such as aero-enginesis described in EP-0859105-A and comprises a flexible plastics materialcover sheet connected to a base sheet thereby to define an essentiallyclosed space within which the article to be stored may be positioned.One or more low-power fans are arranged to direct air into the chamberdefined by the two sheets so as to inflate the space and so form thestorage chamber. In order to prevent condensation within the chamber,which could damage for example paintwork on a vintage car, it is alsoknown to treat the air entering the chamber, for example with avapour-phase corrosion inhibitor and also to ensure that the air in thechamber is slowly replaced by fresh air from the external atmosphere.

SUMMARY OF THE INVENTION

A problem with inflatable storage chambers as described above is that inthe event the relative humidity of the external atmosphere is high,condensation can still occur inside the storage chamber, especiallyshould the external temperature fall. At times, it may be better torecirculate the air within the chamber rather then introduce fresh airhaving a relatively high humidity, particularly if the humidity of theair inside the chamber is lower than that outside the chamber. It wouldbe possible to arrange manually openable and closeable vents to allowcontrol, but an aim of inflatable storage chambers as described inEP-0859105-A is that products may be stored for long periods without theneed for any manual intervention, for example, should the climaticconditions change.

Fan units for the filtration of air are known for example fromDE-29916321-U1, but this fan unit is intended as part of an ultra-cleanroom for use in pharmaceutical or bio-technical fields and is not reallysuitable for use with a storage chamber for a motor vehicle.

In view of the above it is a principal aim of the present invention toprovide an inflatable storage chamber with a fan assembly, to enhancethe storage conditions within the chamber. In particular, improvedstorage conditions can be achieved, with particular reference toreducing the likelihood of condensation within the chamber.

Accordingly, one aspect of the present invention provides a storagechamber comprising an essentially closed space defined by a base sheet,flexible plastics material cover the periphery of which is connected tothe base sheet but which cover is at least partially releasable from thebase sheet to give access to the space, and a fan assembly including anelectrically-driven fan being mounted to an opening through the cover todrive air into the essentially closed space to inflate the chamber,characterised in that the fan assembly has a base plate defining anaperture therethrough and is adapted for mounting to said openingthrough the cover, and a first plenum chamber is formed on the upstreamside of the fan whereby the fan draws air from the first plenum chamberand drives that air through the aperture in the base plate into saidspace, the fan assembly further including an air treatment unit disposedin or over a further opening through the base plate between said spaceand the first plenum chamber and a first filter disposed in or over anopening between the first plenum chamber and the external atmosphere,whereby the air driven into said space is a mixture of air drawn fromthe external atmosphere through the first filter and air drawn from saidspace through the air treatment unit into the first plenum chamber whichlatter air is recirculated into the space.

It will be appreciated that when the storage chamber of this inventionis inflated and ventilated by operation of the fan assembly, some of theair already within the chamber is recirculated by the fan but duringthat recirculation is mixed with fresh air drawn in from the externalatmosphere, through the first filter. In this way, the replacement ofair within the chamber by filtered air from the external atmosphere isreduced. This will lead to a reduction in the wastage of any treatmentagent which may be entrained in the air flow into the chamber. Moreover,the rate of change of the relative humidity of the air in the chambercan be significantly reduced, so in turn minimising the likelihood ofdamaging condensation on articles stored within the chamber.

Depending upon the kind of storage chamber and the products to be storedtherein, the air treatment unit may take a number of different forms.For example, it could comprise a simple second filter, though perhaps ofa different filtering capacity or pore size from those of the firstfilter. Alternatively the second filter could be of a different kind,such as an activated carbon filter.

The second filter may be provided within or sealed to the aperture inthe base plate and may itself have an opening within which is mountedthe fan. In the alternative, the fan may be mounted in an openingthrough a block of firm but resilient material, which resilient materialis supported in or over the aperture through the base plate.

Another possibility for the air treatment unit is for it to includemeans to entrain a treatment liquid in the airflow from the closed spaceto the first plenum chamber. Such a treatment liquid could comprise aknown form of a vapour-phase corrosion inhibitor to reduce thelikelihood of corrosion of an article stored within the chamber. Anotherpossibility is for the air treatment unit to include means to cool theairflow from the storage chamber to the first plenum chamber. Providedsufficient cooling of that airflow occurs, moisture in the airflow maycondense out thereby reducing the moisture content of the airflowre-entering the chamber. In this case, a drain to the exterior of thestorage chamber may be provided, to discharge any such condensate forinstance into a container. Essentially the same effect may be achievedby including within the air treatment unit a suitable desiccant.

The fan assembly may have a second plenum chamber arranged between thesecond filter and the external atmosphere with a third filter disposedin relation to that second plenum chamber to filter air entering thesecond plenum chamber from the external atmosphere. Such a third filtermay be secured to the base plate to overlie with clearance the firstfilter whereby the second plenum chamber is defined by the first andthird filters and the base plate.

The third filter may comprise a multi-layer fibrous filter preferablyconstructed from weather-resistant and waterproof materials. Bycontrast, the first filter may comprise a porous open-cellular structureof a smaller pore size than that of the third filter.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example only, certain specific embodiments of this inventionwill now be described in detail, reference being made to theaccompanying drawings, in which:

FIG. 1 is a diagrammatic perspective view, partially cut away, of aninflatable storage chamber including a pair of fan assemblies, whichchamber is arranged in accordance with this invention;

FIG. 2 is a vertical section through a first embodiment of a fanassembly, for use with the storage chamber of FIG. 1; and

FIGS. 3, 4 and 5 are views similar to that of FIG. 2, but respectivelythrough second, third and fourth embodiments of a fan assembly.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially to FIG. 1, there is shown an inflatable storagechamber of a generally known kind. This storage chamber comprises aplastics material base sheet 10 to which is releasably secured a coversheet 11 preformed to have a generally rectangular shape, when viewed incross-section both transversely and longitudinally. A two-part fastener12 has a first part which extends around the lower edge of the coversheet 11 and a second part which extends around the periphery of thebase sheet 10, the two parts of the fastener being connectable togetherso as to secure the cover sheet 11 to the base sheet 10. For example,the fastener 12 may be a plastic clasp fastener (such as of the kindgenerally sold under the trade mark Zip) or may be a hook and loopfastener (such as of the kind generally sold under the trade markVelcro). Whichever form of fastener is employed, the cover sheet 11should relatively easily be releasable from the base sheet but when thefastener connects the cover sheet to the base sheet, the two sheetsshould securely be held together.

Two circular holes are formed in an end wall 13 of the cover sheet 11and in each of those holes is mounted a respective fan assembly 14.Those assemblies 14 are arranged to draw air from the externalatmosphere and drive that air into the storage chamber. During aninitial period of operation, the fan assemblies will inflate the chambersuch that the air pressure within the chamber becomes super-atmospheric,whereafter the pressure within the storage chamber will be maintained.Any air leaking through the fastener 12 will be replaced by fresh airdrawn from the external atmosphere. In addition to the leakage throughthe fastener vents (not shown) may be provided through the cover sheet11, which vents may be adjusted in order to control the outflow of airfrom the storage chamber.

Referring now to FIG. 2, there is shown a cross-section through one ofthe fan assemblies 14, mounted in the end wall 13. The fan assemblycomprises a base plate 17 including a peripheral flange 18 by means ofwhich the base plate is secured to the hole in the end wall 13 of thestorage chamber. For this purpose, the material of the end wall may bereinforced for example with a second, relatively stiff annular piece 19of plastics material bonded the material of the end wall so as tosurround the hole, with the flange 18 sandwiched between the secondpiece 19 and the material of the end wall itself.

The base plate 17 defines a circular aperture 21 therethrough with afirst filter 22 of a porous open cell structure mounted to the edges 23of that aperture. The base plate also defines a recess 24 in the regionof the aperture 21, within which recess is positioned an activatedcarbon filter 25. An orifice 26 extends through the carbon filter 25 andan electrically driven fan is fitted into that orifice 26. Though showndiagramatically in FIG. 2, the fan comprises an impeller 28 mounted onthe shaft of an electric motor (not shown) supported within a frame 29,which frame is positioned within the orifice 26. The motor typically isa low voltage dc motor and the overall fan may be similar to thosewidely employed in the computer industry, for cooling power supplies andthe like. The fan may additionally be supported by means of an insulator30 connecting the fan frame 29 back to the base plate 17, to relieveloads on the activated carbon filter 25.

In the above manner, a first plenum chamber 31 is defined between theactivated carbon filter 25, the base plate 17 and the first filter 22.Upon operation of the fan 27 to drive air into the storage chamber onwhich the fan assembly is mounted, air may enter the plenum chamber 31either through the first filter 22 or through the activated carbonfilter 25.

A second filter 33 of generally convex form has its periphery supportedon lips 34 provided on the base plate 17, so as to extend over the firstfilter 22 but with clearance thereby to define a second plenum chamber35. Thus, air passing through the first filter 22 to enter the firstplenum chamber 31 must initially pass through the second filter 33 fromthe external atmosphere, to enter the second plenum chamber 35.

In normal operation, the air driven into the storage chamber willconsist of a mixture of air drawn from that storage chamber to berecirculated and also a small quantity of air drawn from outside thestorage chamber, to replace losses from the chamber. So long as thestorage chamber remains inflated, the first plenum chamber 31 will be ata super-atmospheric pressure by virtue of the returning airflow fromwithin the chamber, In this way the flow of air from outside the storagechamber through the second filter 33 will largely be restricted by thesuper-atmospheric pressure within the first plenum chamber 31. Only inthe event that the leakage out of the storage chamber is such that thepressure will start to fall within the chamber will air flow into thefirst plenum chamber from the second plenum chamber, to make good thelosses.

During initial inflation of the storage chamber, all of the air drivenby the fan into the storage chamber will be used to inflate the chamber.Thus, there will be no return flow through the activated carbon filter25 into the first plenum chamber 31 during this stage of the operation;rather, all of the air driven by the fan into the chamber will bederived from the second plenum chamber 35.

In order to achieve the above functionality it is important that thefirst filter 22 and the second filter 33 have appropriatecharacteristics, which may easily be determined empirically. For examplethe first filter 22 may be of an open cellular form with a relativelysmall pore size and the second filter 33 may comprise a multi-layerfibrous filter with a greater pore size. The second filter 33 may be ofweather resistant materials though as shown in FIG. 1 the fan assemblymay be protected by means of a louvre cover 36.

FIG. 3 shows a second embodiment of the fan assembly generally similarto that of FIG. 2 and like parts are given like reference characters;those parts will not be described again here.

In the arrangement of FIG. 3 the activated carbon filter 25 of FIG. 2 isreplaced by an open cell polyurethane foam filter 38. A liquid storagevessel 39 is disposed over the filter 38 and has a nozzle 40 having anorifice to control the outflow of liquid from the vessel into the filter38. In this way, the filter 38 will become impregnated with the liquidfrom the vessel 39 and the air flow through that filter will thusentrain the liquid, in vapour form. In turn, the air flow entering thechamber will carry the vapour, to treat whatever article might bepositioned within the chamber. Typically, the liquid within the vessel39 is a vapour-phase corrosion inhibitor, but could instead be someother chemical—for example a fumigant or insecticide.

FIG. 3 shows a third fan assembly and again like parts with those of theprevious embodiments are given like reference characters and will not bedescribed again here. The fan 27 is carried on a firm but resilient foammount 41 pressed into a recess in the base plate 42 similar to baseplate 17. Base plate 42 also provides a cell 43, a further opening 44through the base plate communicating with the interior of the cell.Mounted within that cell 43 is a Peltier element 45 having fins 46whereby operation of the Peltier element will cool air flowing over thatelement. Provided the cooling is sufficiently great, moisture in the airflow from the storage chamber and passing over the element will condenseout to fall into a water trap 47 at the bottom of the cell 43. Adrainpipe 48 leads away from the water trap 47 to the exterior of thestorage chamber.

In other respects, the arrangement of FIG. 4 operates substantially ashas been described above with reference FIG. 2.

FIG. 5 shows yet another embodiment of fan assembly. This assembly issimilar to that of FIG. 4; like parts are given like reference numbersand will not be described again here. In the arrangement of FIG. 5 thePeltier element 45 is replaced by a desiccant 49 provided in a porousbag or provided on a card. The desiccant will draw moisture out of theair flow being recirculated by the fan. As with the previous embodiment,once the desiccant has become saturated the water will fall into a watertrap 47 and so to a drain pipe 48 to be led away from the storagechamber.

1. A storage chamber comprising an essentially closed space defined by abase sheet, flexible plastics material cover having a periphery which isconnected to the base sheet but which cover is at least partiallyreleasable from the base sheet to give access to the space, the coverhaving an opening therethrough, and a fan assembly including anelectrically-driven fan mounted to the opening through the cover todrive air into the essentially closed space to inflate the chamber,characterised in that the fan assembly has a base plate defining anaperture therethrough which base plate is mounted to said cover withsaid aperture in register with the opening through the cover, and afirst plenum chamber is formed on the upstream side of the fan wherebythe fan draws air from the first plenum chamber and drives that airthrough the aperture in the base plate into said space, the fan assemblyfurther including an air treatment unit disposed in or over a furtheropening through the base plate between said space and the first plenumchamber and a first filter disposed in or over an opening between thefirst plenum chamber and the external atmosphere, whereby the air driveninto said space is a mixture of air drawn from the external atmospherethrough the first filter and air drawn from said space through the airtreatment unit into the first plenum chamber which latter air iscirculated into the space.
 2. A storage chamber as claimed in claim 1,wherein the air treatment unit comprises a second filter.
 3. A storagechamber as claimed in claim 2, wherein the second filter comprises anactivated carbon filter.
 4. A storage chamber as claimed in claim 2,wherein the second filter is provided within said aperture in the baseplate and the fan is mounted in an opening formed through the filter. 5.A storage chamber as claimed in claim 1, wherein the fan is mounted inan opening through a block of resilient material which resilientmaterial is supported in the aperture through the base plate.
 6. Astorage chamber as claimed in claim 1, wherein the air treatment unitincludes means to entrain a treatment liquid in the air flow from saidspace to the first plenum chamber.
 7. A storage chamber as claimed inclaim 6, wherein the treatment liquid comprises a vapour-phase corrosioninhibitor to assist in corrosion-prevention of an article stored in saidspace.
 8. A storage chamber as claimed in claim 1, wherein the airtreatment unit includes means to cool the air flow from said space tothe first plenum chamber.
 9. A storage chamber as claimed in claim 8,wherein the air treatment unit includes a drain for liquid condensedfrom the air flow, thereby to reduce the moisture content of that airflow.
 10. A storage chamber as claimed in claim 1, wherein the airtreatment unit includes a desiccant to remove moisture from the air flowfrom said space to the first plenum chamber.
 11. A storage chamber asclaimed in claim 1, wherein there is a second plenum chamber arrangedbetween the second filter and the external atmosphere, with a thirdfilter disposed in relation to that second plenum chamber to filter airentering the second plenum chamber from the external atmosphere.
 12. Astorage chamber as claimed in claim 11, wherein the third filter issecured to the base plate to overlie with clearance the first filterthereby to define in conjunction therewith the second plenum chamber.13. A storage chamber as claimed in claim 11, wherein the third filtercomprises a multi-layer fibrous filter constructed from weatherresistant materials.
 14. A storage chamber as claimed in claim 1,wherein the first filter comprises a porous filter having an opencellular structure.